富烧绿石型人造岩石固化模拟锕系元素废液的研究

IMMOBILIZATION OF SIMULATED ACTINIDES IN PYROCHLORE-RICH SYNROC

采用与钙钛锆石 (Zirconolite)性能相近的烧绿石 (Pyrochlore)为主要矿相 ,制备了对锕系元素废液有不同包容量 (37%～ 5 0 % )的人造岩石固化体 ,测定了其物理性能。应用X射线衍射(XRD)、扫描电镜能谱分析 (SEM /EDS)研究了其矿相组成、微观结构和相组分分析 ,并采用产品一致性测试 (PCT)粉末浸泡法研究其抗浸出性能。研究结果表明 ,富烧绿石人造岩石是固化锕系元素废液并最终进行地质处置的理想固化体。

Pyrochlore rich Synroc samples with different simulated actinide waste loading(37 %～50 %) are fabricated and tested. The XRD and SEM/EDS analysis show that the major phase is well concordant with the formulation design. The samples have good physical properties: density(>5.1 g/cm 3),open porosity(<0.2%)and vickers hardness(>1 000 kg/mm 2). The samples leach rates are in the order 10 -3 (for Ca),10 -6 (for Ti) and 10 -7 (for Nd and U) g/(m 2·d), better than that of the Zirconolite rich Synroc samples. Thus the Pyrochlore rich Synroc offers a suitable host to incorporate actinides. It is a durable material even under hydrothermal condition with high waste loading and density, which is in favor for final geological disposal.